/*
** $Id: liolib.c,v 2.111 2013/03/21 13:57:27 roberto Exp $
** Standard I/O (and system) library
** See Copyright Notice in lua.h
*/


/*
** POSIX idiosyncrasy!
** This definition must come before the inclusion of 'stdio.h'; it
** should not affect non-POSIX systems
*/
#if !defined(_FILE_OFFSET_BITS)
#define _FILE_OFFSET_BITS 64
#endif


#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define liolib_c
#define LUA_LIB

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"


#if !defined(lua_checkmode)

/*
** Check whether 'mode' matches '[rwa]%+?b?'.
** Change this macro to accept other modes for 'fopen' besides
** the standard ones.
*/
#define lua_checkmode(mode) \
	(*mode != '\0' && strchr("rwa", *(mode++)) != NULL &&	\
	(*mode != '+' || ++mode) &&  /* skip if char is '+' */	\
	(*mode != 'b' || ++mode) &&  /* skip if char is 'b' */	\
	(*mode == '\0'))

#endif

/*
** {======================================================
** lua_popen spawns a new process connected to the current
** one through the file streams.
** =======================================================
*/

#if !defined(lua_popen)	/* { */

#if defined(LUA_USE_POPEN)	/* { */

#define lua_popen(L,c,m)	((void)L, fflush(NULL), popen(c,m))
#define lua_pclose(L,file)	((void)L, pclose(file))

#elif defined(LUA_WIN)		/* }{ */

#define lua_popen(L,c,m)		((void)L, _popen(c,m))
#define lua_pclose(L,file)		((void)L, _pclose(file))


#else				/* }{ */

#define lua_popen(L,c,m)		((void)((void)c, m),  \
	luaL_error(L, LUA_QL("popen") " not supported"), (FILE*)0)
#define lua_pclose(L,file)		((void)((void)L, file), -1)


#endif				/* } */

#endif			/* } */

/* }====================================================== */


/*
** {======================================================
** lua_fseek/lua_ftell: configuration for longer offsets
** =======================================================
*/

#if !defined(lua_fseek)	/* { */

#if defined(LUA_USE_POSIX)

#define l_fseek(f,o,w)		fseeko(f,o,w)
#define l_ftell(f)		ftello(f)
#define l_seeknum		off_t

#elif defined(LUA_WIN) && !defined(_CRTIMP_TYPEINFO) \
	&& defined(_MSC_VER) && (_MSC_VER >= 1400)
/* Windows (but not DDK) and Visual C++ 2005 or higher */

#define l_fseek(f,o,w)		_fseeki64(f,o,w)
#define l_ftell(f)		_ftelli64(f)
#define l_seeknum		__int64

#else

#define l_fseek(f,o,w)		fseek(f,o,w)
#define l_ftell(f)		ftell(f)
#define l_seeknum		long

#endif

#endif			/* } */

/* }====================================================== */


#define IO_PREFIX	"_IO_"
#define IO_INPUT	(IO_PREFIX "input")
#define IO_OUTPUT	(IO_PREFIX "output")


typedef luaL_Stream LStream;


#define tolstream(L)	((LStream *)luaL_checkudata(L, 1, LUA_FILEHANDLE))

#define isclosed(p)	((p)->closef == NULL)


static int io_type (lua_State *L) {
	LStream *p;
	luaL_checkany(L, 1);
	p = (LStream *)luaL_testudata(L, 1, LUA_FILEHANDLE);
	if (p == NULL)
		lua_pushnil(L);  /* not a file */
	else if (isclosed(p))
		lua_pushliteral(L, "closed file");
	else
		lua_pushliteral(L, "file");
	return 1;
}


static int f_tostring (lua_State *L) {
	LStream *p = tolstream(L);
	if (isclosed(p))
		lua_pushliteral(L, "file (closed)");
	else
		lua_pushfstring(L, "file (%p)", p->f);
	return 1;
}


static FILE *tofile (lua_State *L) {
	LStream *p = tolstream(L);
	if (isclosed(p))
		luaL_error(L, "attempt to use a closed file");
	lua_assert(p->f);
	return p->f;
}


/*
** When creating file handles, always creates a `closed' file handle
** before opening the actual file; so, if there is a memory error, the
** file is not left opened.
*/
static LStream *newprefile (lua_State *L) {
	LStream *p = (LStream *)lua_newuserdata(L, sizeof(LStream));
	p->closef = NULL;  /* mark file handle as 'closed' */
	luaL_setmetatable(L, LUA_FILEHANDLE);
	return p;
}


static int aux_close (lua_State *L) {
	LStream *p = tolstream(L);
	lua_CFunction cf = p->closef;
	p->closef = NULL;  /* mark stream as closed */
	return (*cf)(L);  /* close it */
}


static int io_close (lua_State *L) {
	if (lua_isnone(L, 1))  /* no argument? */
		lua_getfield(L, LUA_REGISTRYINDEX, IO_OUTPUT);  /* use standard output */
	tofile(L);  /* make sure argument is an open stream */
	return aux_close(L);
}


static int f_gc (lua_State *L) {
	LStream *p = tolstream(L);
	if (!isclosed(p) && p->f != NULL)
		aux_close(L);  /* ignore closed and incompletely open files */
	return 0;
}


/*
** function to close regular files
*/
static int io_fclose (lua_State *L) {
	LStream *p = tolstream(L);
	int res = fclose(p->f);
	return luaL_fileresult(L, (res == 0), NULL);
}


static LStream *newfile (lua_State *L) {
	LStream *p = newprefile(L);
	p->f = NULL;
	p->closef = &io_fclose;
	return p;
}


static void opencheck (lua_State *L, const char *fname, const char *mode) {
	LStream *p = newfile(L);
	p->f = fopen(fname, mode);
	if (p->f == NULL)
		luaL_error(L, "cannot open file " LUA_QS " (%s)", fname, strerror(errno));
}


static int io_open (lua_State *L) {
	const char *filename = luaL_checkstring(L, 1);
	const char *mode = luaL_optstring(L, 2, "r");
	LStream *p = newfile(L);
	const char *md = mode;  /* to traverse/check mode */
	luaL_argcheck(L, lua_checkmode(md), 2, "invalid mode");
	p->f = fopen(filename, mode);
	return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1;
}


/*
** function to close 'popen' files
*/
static int io_pclose (lua_State *L) {
	LStream *p = tolstream(L);
	return luaL_execresult(L, lua_pclose(L, p->f));
}


static int io_popen (lua_State *L) {
	const char *filename = luaL_checkstring(L, 1);
	const char *mode = luaL_optstring(L, 2, "r");
	LStream *p = newprefile(L);
	p->f = lua_popen(L, filename, mode);
	p->closef = &io_pclose;
	return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1;
}


static int io_tmpfile (lua_State *L) {
	LStream *p = newfile(L);
	p->f = tmpfile();
	return (p->f == NULL) ? luaL_fileresult(L, 0, NULL) : 1;
}


static FILE *getiofile (lua_State *L, const char *findex) {
	LStream *p;
	lua_getfield(L, LUA_REGISTRYINDEX, findex);
	p = (LStream *)lua_touserdata(L, -1);
	if (isclosed(p))
		luaL_error(L, "standard %s file is closed", findex + strlen(IO_PREFIX));
	return p->f;
}


static int g_iofile (lua_State *L, const char *f, const char *mode) {
	if (!lua_isnoneornil(L, 1)) {
		const char *filename = lua_tostring(L, 1);
		if (filename)
			opencheck(L, filename, mode);
		else {
			tofile(L);  /* check that it's a valid file handle */
			lua_pushvalue(L, 1);
		}
		lua_setfield(L, LUA_REGISTRYINDEX, f);
	}
	/* return current value */
	lua_getfield(L, LUA_REGISTRYINDEX, f);
	return 1;
}


static int io_input (lua_State *L) {
	return g_iofile(L, IO_INPUT, "r");
}


static int io_output (lua_State *L) {
	return g_iofile(L, IO_OUTPUT, "w");
}


static int io_readline (lua_State *L);


static void aux_lines (lua_State *L, int toclose) {
	int i;
	int n = lua_gettop(L) - 1;  /* number of arguments to read */
	/* ensure that arguments will fit here and into 'io_readline' stack */
	luaL_argcheck(L, n <= LUA_MINSTACK - 3, LUA_MINSTACK - 3, "too many options");
	lua_pushvalue(L, 1);  /* file handle */
	lua_pushinteger(L, n);  /* number of arguments to read */
	lua_pushboolean(L, toclose);  /* close/not close file when finished */
	for (i = 1; i <= n; i++) lua_pushvalue(L, i + 1);  /* copy arguments */
	lua_pushcclosure(L, io_readline, 3 + n);
}


static int f_lines (lua_State *L) {
	tofile(L);  /* check that it's a valid file handle */
	aux_lines(L, 0);
	return 1;
}


static int io_lines (lua_State *L) {
	int toclose;
	if (lua_isnone(L, 1)) lua_pushnil(L);  /* at least one argument */
	if (lua_isnil(L, 1)) {  /* no file name? */
		lua_getfield(L, LUA_REGISTRYINDEX, IO_INPUT);  /* get default input */
		lua_replace(L, 1);  /* put it at index 1 */
		tofile(L);  /* check that it's a valid file handle */
		toclose = 0;  /* do not close it after iteration */
	}
	else {  /* open a new file */
		const char *filename = luaL_checkstring(L, 1);
		opencheck(L, filename, "r");
		lua_replace(L, 1);  /* put file at index 1 */
		toclose = 1;  /* close it after iteration */
	}
	aux_lines(L, toclose);
	return 1;
}


/*
** {======================================================
** READ
** =======================================================
*/


static int read_number (lua_State *L, FILE *f) {
	lua_Number d;
	if (fscanf(f, LUA_NUMBER_SCAN, &d) == 1) {
		lua_pushnumber(L, d);
		return 1;
	}
	else {
		lua_pushnil(L);  /* "result" to be removed */
		return 0;  /* read fails */
	}
}


static int test_eof (lua_State *L, FILE *f) {
	int c = getc(f);
	ungetc(c, f);
	lua_pushlstring(L, NULL, 0);
	return (c != EOF);
}


static int read_line (lua_State *L, FILE *f, int chop) {
	luaL_Buffer b;
	luaL_buffinit(L, &b);
	for (;;) {
		size_t l;
		char *p = luaL_prepbuffer(&b);
		if (fgets(p, LUAL_BUFFERSIZE, f) == NULL) {  /* eof? */
			luaL_pushresult(&b);  /* close buffer */
			return (lua_rawlen(L, -1) > 0);  /* check whether read something */
		}
		l = strlen(p);
		if (l == 0 || p[l-1] != '\n')
			luaL_addsize(&b, l);
		else {
			luaL_addsize(&b, l - chop);  /* chop 'eol' if needed */
			luaL_pushresult(&b);  /* close buffer */
			return 1;  /* read at least an `eol' */
		}
	}
}


#define MAX_SIZE_T	(~(size_t)0)

static void read_all (lua_State *L, FILE *f) {
	size_t rlen = LUAL_BUFFERSIZE;  /* how much to read in each cycle */
	luaL_Buffer b;
	luaL_buffinit(L, &b);
	for (;;) {
		char *p = luaL_prepbuffsize(&b, rlen);
		size_t nr = fread(p, sizeof(char), rlen, f);
		luaL_addsize(&b, nr);
		if (nr < rlen) break;  /* eof? */
		else if (rlen <= (MAX_SIZE_T / 4))  /* avoid buffers too large */
			rlen *= 2;  /* double buffer size at each iteration */
	}
	luaL_pushresult(&b);  /* close buffer */
}


static int read_chars (lua_State *L, FILE *f, size_t n) {
	size_t nr;  /* number of chars actually read */
	char *p;
	luaL_Buffer b;
	luaL_buffinit(L, &b);
	p = luaL_prepbuffsize(&b, n);  /* prepare buffer to read whole block */
	nr = fread(p, sizeof(char), n, f);  /* try to read 'n' chars */
	luaL_addsize(&b, nr);
	luaL_pushresult(&b);  /* close buffer */
	return (nr > 0);  /* true iff read something */
}


static int g_read (lua_State *L, FILE *f, int first) {
	int nargs = lua_gettop(L) - 1;
	int success;
	int n;
	clearerr(f);
	if (nargs == 0) {  /* no arguments? */
		success = read_line(L, f, 1);
		n = first+1;  /* to return 1 result */
	}
	else {  /* ensure stack space for all results and for auxlib's buffer */
		luaL_checkstack(L, nargs+LUA_MINSTACK, "too many arguments");
		success = 1;
		for (n = first; nargs-- && success; n++) {
			if (lua_type(L, n) == LUA_TNUMBER) {
				size_t l = (size_t)lua_tointeger(L, n);
				success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l);
			}
			else {
				const char *p = lua_tostring(L, n);
				luaL_argcheck(L, p && p[0] == '*', n, "invalid option");
				switch (p[1]) {
				case 'n':  /* number */
					success = read_number(L, f);
					break;
				case 'l':  /* line */
					success = read_line(L, f, 1);
					break;
				case 'L':  /* line with end-of-line */
					success = read_line(L, f, 0);
					break;
				case 'a':  /* file */
					read_all(L, f);  /* read entire file */
					success = 1; /* always success */
					break;
				default:
					return luaL_argerror(L, n, "invalid format");
				}
			}
		}
	}
	if (ferror(f))
		return luaL_fileresult(L, 0, NULL);
	if (!success) {
		lua_pop(L, 1);  /* remove last result */
		lua_pushnil(L);  /* push nil instead */
	}
	return n - first;
}


static int io_read (lua_State *L) {
	return g_read(L, getiofile(L, IO_INPUT), 1);
}


static int f_read (lua_State *L) {
	return g_read(L, tofile(L), 2);
}


static int io_readline (lua_State *L) {
	LStream *p = (LStream *)lua_touserdata(L, lua_upvalueindex(1));
	int i;
	int n = (int)lua_tointeger(L, lua_upvalueindex(2));
	if (isclosed(p))  /* file is already closed? */
		return luaL_error(L, "file is already closed");
	lua_settop(L , 1);
	for (i = 1; i <= n; i++)  /* push arguments to 'g_read' */
		lua_pushvalue(L, lua_upvalueindex(3 + i));
	n = g_read(L, p->f, 2);  /* 'n' is number of results */
	lua_assert(n > 0);  /* should return at least a nil */
	if (!lua_isnil(L, -n))  /* read at least one value? */
		return n;  /* return them */
	else {  /* first result is nil: EOF or error */
		if (n > 1) {  /* is there error information? */
			/* 2nd result is error message */
			return luaL_error(L, "%s", lua_tostring(L, -n + 1));
		}
		if (lua_toboolean(L, lua_upvalueindex(3))) {  /* generator created file? */
			lua_settop(L, 0);
			lua_pushvalue(L, lua_upvalueindex(1));
			aux_close(L);  /* close it */
		}
		return 0;
	}
}

/* }====================================================== */


static int g_write (lua_State *L, FILE *f, int arg) {
	int nargs = lua_gettop(L) - arg;
	int status = 1;
	for (; nargs--; arg++) {
		if (lua_type(L, arg) == LUA_TNUMBER) {
			/* optimization: could be done exactly as for strings */
			status = status &&
				fprintf(f, LUA_NUMBER_FMT, lua_tonumber(L, arg)) > 0;
		}
		else {
			size_t l;
			const char *s = luaL_checklstring(L, arg, &l);
			status = status && (fwrite(s, sizeof(char), l, f) == l);
		}
	}
	if (status) return 1;  /* file handle already on stack top */
	else return luaL_fileresult(L, status, NULL);
}


static int io_write (lua_State *L) {
	return g_write(L, getiofile(L, IO_OUTPUT), 1);
}


static int f_write (lua_State *L) {
	FILE *f = tofile(L);
	lua_pushvalue(L, 1);  /* push file at the stack top (to be returned) */
	return g_write(L, f, 2);
}


static int f_seek (lua_State *L) {
	static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END};
	static const char *const modenames[] = {"set", "cur", "end", NULL};
	FILE *f = tofile(L);
	int op = luaL_checkoption(L, 2, "cur", modenames);
	lua_Number p3 = luaL_optnumber(L, 3, 0);
	l_seeknum offset = (l_seeknum)p3;
	luaL_argcheck(L, (lua_Number)offset == p3, 3,
		"not an integer in proper range");
	op = l_fseek(f, offset, mode[op]);
	if (op)
		return luaL_fileresult(L, 0, NULL);  /* error */
	else {
		lua_pushnumber(L, (lua_Number)l_ftell(f));
		return 1;
	}
}


static int f_setvbuf (lua_State *L) {
	static const int mode[] = {_IONBF, _IOFBF, _IOLBF};
	static const char *const modenames[] = {"no", "full", "line", NULL};
	FILE *f = tofile(L);
	int op = luaL_checkoption(L, 2, NULL, modenames);
	lua_Integer sz = luaL_optinteger(L, 3, LUAL_BUFFERSIZE);
	int res = setvbuf(f, NULL, mode[op], sz);
	return luaL_fileresult(L, res == 0, NULL);
}



static int io_flush (lua_State *L) {
	return luaL_fileresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL);
}


static int f_flush (lua_State *L) {
	return luaL_fileresult(L, fflush(tofile(L)) == 0, NULL);
}


/*
** functions for 'io' library
*/
static const luaL_Reg iolib[] = {
	{"close", io_close},
	{"flush", io_flush},
	{"input", io_input},
	{"lines", io_lines},
	{"open", io_open},
	{"output", io_output},
	{"popen", io_popen},
	{"read", io_read},
	{"tmpfile", io_tmpfile},
	{"type", io_type},
	{"write", io_write},
	{NULL, NULL}
};


/*
** methods for file handles
*/
static const luaL_Reg flib[] = {
	{"close", io_close},
	{"flush", f_flush},
	{"lines", f_lines},
	{"read", f_read},
	{"seek", f_seek},
	{"setvbuf", f_setvbuf},
	{"write", f_write},
	{"__gc", f_gc},
	{"__tostring", f_tostring},
	{NULL, NULL}
};


static void createmeta (lua_State *L) {
	luaL_newmetatable(L, LUA_FILEHANDLE);  /* create metatable for file handles */
	lua_pushvalue(L, -1);  /* push metatable */
	lua_setfield(L, -2, "__index");  /* metatable.__index = metatable */
	luaL_setfuncs(L, flib, 0);  /* add file methods to new metatable */
	lua_pop(L, 1);  /* pop new metatable */
}


/*
** function to (not) close the standard files stdin, stdout, and stderr
*/
static int io_noclose (lua_State *L) {
	LStream *p = tolstream(L);
	p->closef = &io_noclose;  /* keep file opened */
	lua_pushnil(L);
	lua_pushliteral(L, "cannot close standard file");
	return 2;
}


static void createstdfile (lua_State *L, FILE *f, const char *k,
						   const char *fname) {
							   LStream *p = newprefile(L);
							   p->f = f;
							   p->closef = &io_noclose;
							   if (k != NULL) {
								   lua_pushvalue(L, -1);
								   lua_setfield(L, LUA_REGISTRYINDEX, k);  /* add file to registry */
							   }
							   lua_setfield(L, -2, fname);  /* add file to module */
}


LUAMOD_API int luaopen_io (lua_State *L) {
	luaL_newlib(L, iolib);  /* new module */
	createmeta(L);
	/* create (and set) default files */
	createstdfile(L, stdin, IO_INPUT, "stdin");
	createstdfile(L, stdout, IO_OUTPUT, "stdout");
	createstdfile(L, stderr, NULL, "stderr");
	return 1;
}

